How many hotel rooms should you block for your wedding?

Count only the guests who need a hotel bed: take your guest list, subtract local guests and anyone sleeping at the venue, and divide by the number of people per room, often two. The Box House Hotel’s working rule is to expect 60 to 70 percent of out-of-town guests to book inside the block, at roughly one room per two guests. If you are unsure, start smaller and ask the hotel whether you can add rooms later.

A courtesy block holds rooms at a group rate until a cutoff date, then releases any unbooked rooms back to the hotel with no charge to you. A contracted block, also called a guaranteed or attrition block, commits you to a share of the rooms being booked. If your guests book fewer, you can be billed for the shortfall. Each hotel sets its own policy, so ask which kind it is offering before you sign.

Attrition is the share of a contracted block your guests must book by the cutoff date. The Knot puts the standard target at 80 to 90 percent; Where Will They Stay puts it at 70 to 90 percent. Their example: 20 rooms for 2 nights at 80 percent means your guests need to book 32 room nights, and unbooked room nights below that can be charged to you. Ask whether the hotel counts attrition per night or across the whole stay.

The Knot and the Association of Bridal Consultants both put the typical cutoff at about 30 days before check-in. After it, the hotel can release unbooked rooms to the public. Guests can still book, but the group rate is no longer guaranteed. Put the cutoff date everywhere you share the hotel details.

A planner quoted by The Knot suggests securing room blocks 9 to 12 months before the wedding, especially in popular cities or peak season, and setting the block up before save the dates go out, since many guests book travel as soon as they hear the date.

Fewer of them. Everyone who sleeps at the venue needs no hotel room, so at an estate or rental with bedrooms the block covers only the guests left over. How many people a venue sleeps differs by listing, so check each one. If only a few rooms are left, note that The Knot says some hotels ask for a minimum of 10 to 15 rooms per night, so a small courtesy block or a short list of nearby hotels may suit you better.